Explanation: An Electronic Access Control (EAC) token is best known for its ability to overcome the problems of key assignments in a physical security system. An EAC token is a device that can be used to authenticate a user or grant access to a physical area or resource, such as a door, a gate, or a locker2. An EAC token can be a smart card, a magnetic stripe card, a proximity card, a key fob, or a biometric device. An EAC token can overcome the problems of key assignments, which are the issues or challenges of managing and distributing physical keys to authorized users, such as lost, stolen, duplicated, or unreturned keys. An EAC token can provide more security, convenience, and flexibility than a physical key, as it can be easily activated, deactivated, or replaced, and it can also store additional information or perform other functions. Monitoring the opening of windows and doors, triggering alarms when intruders are detected, and locking down a facility during an emergency are not the abilities that an EAC token is best known for, as they are more related to the functions of other components of a physical security system, such as sensors, alarms, or locks. References: 2: CISSP For Dummies, 7th Edition, Chapter 9, page 253.